76 research outputs found

    Domestics I

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    Monitoring Annoyance and Stress Effects of Wind Turbines on Nearby Residents: A Comparison of U.S. and European Samples

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    As wind turbines and the number of wind projects scale throughout the world, a growing number of individuals might be affected by these structures. For some people, wind turbine sounds and their effects on the landscape can be annoying and could even prompt stress reactions. This comparative study analyzed a combined sample of survey respondents from the U.S., Germany and Switzerland. It utilized a newly developed assessment scale (ASScale) to reliably characterize these stress-impacted individuals living within populations near turbines. Findings indicate low prevalence of annoyance, stress symptoms and coping strategies. Noise annoyance stress (NASScale) was negatively correlated with the perceptions of a lack of fairness of the wind project\u27s planning and development process, among other subjective variables. Objective indicators, such as the distance from the nearest turbine and sound pressure level modeled for each respondent, were not found to be correlated to noise annoyance. Similar result patterns were found across the European and U.S. samples

    Resonance frequencies of lipid-shelled microbubbles in the regime of nonlinear oscillations

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    Knowledge of resonant frequencies of contrast microbubbles is important for the optimization of ultrasound contrast imaging and therapeutic techniques. To date, however, there are estimates of resonance frequencies of contrast microbubbles only for the regime of linear oscillation. The present paper proposes an approach for evaluating resonance frequencies of contrast agent microbubbles in the regime of nonlinear oscillation. The approach is based on the calculation of the time-averaged oscillation power of the radial bubble oscillation. The proposed procedure was verified for free bubbles in the frequency range 1–4 MHz and then applied to lipid-shelled microbubbles insonified with a single 20-cycle acoustic pulse at two values of the acoustic pressure amplitude, 100 kPa and 200 kPa, and at four frequencies: 1.5, 2.0, 2.5, and 3.0 MHz. It is shown that, as the acoustic pressure amplitude is increased, the resonance frequency of a lipid-shelled microbubble tends to decrease in comparison with its linear resonance frequency. Analysis of existing shell models reveals that models that treat the lipid shell as a linear viscoelastic solid appear may be challenged to provide the observed tendency in the behavior of the resonance frequency at increasing acoustic pressure. The conclusion is drawn that the further development of shell models could be improved by the consideration of nonlinear rheological laws

    Modeling of nonlinear viscous stress in encapsulating shells of lipid-coated contrast agent microbubbles

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    A general theoretical approach to the development of zero-thickness encapsulation models for contrast microbubbles is proposed. The approach describes a procedure that allows one to recast available rheological laws from the bulk form to a surface form which is used in a modified Rayleigh-Plesset equation governing the radial dynamics of a contrast microbubble. By the use of the proposed procedure, the testing of different rheological laws for encapsulation can be carried out. Challenges of existing shell models for lipid-encapsulated microbubbles, such as the dependence of shell parameters on the initial bubble radius and the “compression-only” behavior, are discussed. Analysis of the rheological behavior of lipid encapsulation is made by using experimental radius-time curves for lipid-coated microbubbles with radii in the range 1.2 – 2.5 μm. The curves were acquired for a research phospholipid-coated contrast agent insonified with a 20-cycle, 3.0 MHz, 100 kPa acoustic pulse. The fitting of the experimental data by a model which treats the shell as a viscoelastic solid gives the values of the shell surface viscosity increasing from 0.30×10-8 kg/s to 2.63×10-8 kg/s for the range of bubble radii indicated above. The shell surface elastic modulus increases from 0.054 N/m to 0.37 N/m. It is proposed that this increase may be a result of the lipid coating possessing the properties of both a shear-thinning and a strain-softening material. We hypothesize that these complicated rheological properties do not allow the existing shell models to satisfactorily describe the dynamics of lipid encapsulation. In the existing shell models, the viscous and the elastic shell terms have the linear form which assumes that the viscous and the elastic stresses acting inside the lipid shell are proportional to the shell shear rate and the shell strain, respectively, with constant coefficients of proportionality. The analysis performed in the present paper suggests that a more general, nonlinear theory may be more appropriate. It is shown that the use of the nonlinear theory for shell viscosity allows one to model the “compression-only” behavior. As an example, the results of the simulation for a 2.03- μm-radius bubble insonified with a 6-cycle, 1.8 MHz, 100 kPa acoustic pulse are given. These parameters correspond to the acoustic conditions under which the “compression-only” behavior was observed by de Jong et al. [Ultrasound Med. Biol. 33 (2007) 653–656]. It is also shown that the use of the Cross law for the modeling of the shear-thinning behavior of shell viscosity reduces the variance of experimentally estimated values of the shell viscosity and its dependence on the initial bubble radius

    Health care experiences of U.S. Retirees living in Mexico and Panama: a qualitative study

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    Abstract Background Retirement migration from northern countries to southern countries is increasing in both Europe and North America, and retiree experiences will impact future migration and health services utilization. We therefore sought to describe the healthcare experiences and perceptions of retired U.S. citizens currently living in Mexico and Panama. Methods 46 retired U.S. citizens (23 per country) who had been hospitalized (61%) or had a chronic health condition (78%) in two regions per country with large communities of retired U.S. citizens were identified. Detailed semi-structured interviews were conducted to explore experiences with, attitudes toward, and costs of healthcare. Interviews were analyzed using quantitative and qualitative methods. Results Respondents averaged 68–70 years old, were well educated, had few physical dependencies, and had moderate incomes. They praised physician services as more personalized than in the U.S. and home care as inexpensive and widely available, expressed favorable opinions regarding outpatient and dental care, gave mixed ratings on hospital services, and expressed concerns about emergency services. Numerous concerns about health insurance were expressed, including the unavailability of Medicare and reductions in Tricare. Payment concerns and lack of data on local health providers made deciding where to obtain services challenging. Conclusions Retirees living abroad report dilemmas regarding healthcare choices, insurance availability, and quality of care. As this population segment grows, pressure will increase for policy and business solutions to existing medical care challenges

    Task Shifting: The Use of Laypersons for Acquisition of Vital Signs Data for Clinical Decision Making in the Emergency Room Following Traumatic Injury

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    Importance: In resource-limited settings, identification of successful and sustainable task-shifting interventions is important for improving care. Objective: To determine whether the training of lay people to take vital signs as trauma clerks is an effective and sustainable method to increase availability of vital signs in the initial evaluation of trauma patients. Design: We conducted a quasi-experimental study of patients presenting with traumatic injury pre- and post-intervention. Setting: The study was conducted at Kamuzu Central Hospital, a tertiary care referral hospital, in Lilongwe, Malawi. Participants: All adult (age ≥ 18 years) trauma patients presenting to emergency department over a six-month period from January to June prior to intervention (2011), immediately post-intervention (2012), 1 year post-intervention (2013) and 2 years post-intervention (2014). Intervention: Lay people were trained to take and record vital signs. Main outcomes and measures: The number of patients with recorded vital signs pre- and post-intervention and sustainability of the intervention as determined by time-series analysis. Results: Availability of vital signs on initial evaluation of trauma patients increased significantly post-intervention. The percentage of patients with at least one vital sign recorded increased from 23.5 to 92.1%, and the percentage of patients with all vital signs recorded increased from 4.1 to 91.4%. Availability of Glasgow Coma Scale also increased from 40.3 to 88.6%. Increased documentation of vital signs continued at 1 year and 2 years post-intervention. However, the percentage of documented vital signs did decrease slightly after the US-trained medical student and surgeon who trained the trauma clerks were no longer available in country, except for Glasgow Coma Scale. Patients who died during emergency department evaluation were significantly less likely to have vital signs recorded. Conclusions and relevance: The training of lay people to collect vital signs and Glasgow Coma Scale is an effective and sustainable method of task shifting in a resource-limited setting

    Health care experiences of U.S. Retirees living in Mexico and Panama: a qualitative study

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    Abstract Background Retirement migration from northern countries to southern countries is increasing in both Europe and North America, and retiree experiences will impact future migration and health services utilization. We therefore sought to describe the healthcare experiences and perceptions of retired U.S. citizens currently living in Mexico and Panama. Methods 46 retired U.S. citizens (23 per country) who had been hospitalized (61%) or had a chronic health condition (78%) in two regions per country with large communities of retired U.S. citizens were identified. Detailed semi-structured interviews were conducted to explore experiences with, attitudes toward, and costs of healthcare. Interviews were analyzed using quantitative and qualitative methods. Results Respondents averaged 68–70 years old, were well educated, had few physical dependencies, and had moderate incomes. They praised physician services as more personalized than in the U.S. and home care as inexpensive and widely available, expressed favorable opinions regarding outpatient and dental care, gave mixed ratings on hospital services, and expressed concerns about emergency services. Numerous concerns about health insurance were expressed, including the unavailability of Medicare and reductions in Tricare. Payment concerns and lack of data on local health providers made deciding where to obtain services challenging. Conclusions Retirees living abroad report dilemmas regarding healthcare choices, insurance availability, and quality of care. As this population segment grows, pressure will increase for policy and business solutions to existing medical care challenges

    Injury Characteristics and Outcomes in Elderly Trauma Patients in Sub-Saharan Africa

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    Background: Traumatic injury in the elderly is an emerging global problem with an associated increase in morbidity and mortality. This study sought to describe the epidemiology of elderly injury and outcomes in sub-Saharan Africa. Methods: We conducted a retrospective analysis of adult patients (≥ 18 years) with traumatic injuries presenting to the Kamuzu Central Hospital (KCH) in Lilongwe, Malawi, over 5 years (2009–2013). Elderly patients were defined as adults aged ≥65 years and compared to adults aged 18–44 and 45–64 years. We used propensity score matching and logistic regression to compare the odds of mortality between age groups using the youngest age group as the reference. Results: 42,816 Adult patients with traumatic injuries presented to KCH during the study period. 1253 patients (2.9 %) were aged ≥65 years with a male preponderance (77.4 %). Injuries occurred more often at home as age increased (25.3, 29.5, 41.1 %, p < 0.001) and falls were more common (14.1, 23.8, 36.3 %, p < 0.001) for elderly patients. Elderly age was associated with a higher proportion of hospital admissions (10.6, 21.3, 35.2 %, p < 0.001). Upon propensity score matching and logistic regression analysis, the odds ratio of mortality for patients aged ≥65 was 3.15 (95 % CI 1.45, 6.82, p = 0.0037) compared to the youngest age group (18–44 years). Conclusions: Elderly trauma in a resource-poor area in sub-Saharan Africa is associated with a significant increase in hospital admissions and mortality. Significant improvements in trauma systems, pre-hospital care, and hospital capacity for older, critically ill patients are imperative

    HIV Testing and Epidemiology in a Hospital-Based Surgical Cohort in Malawi

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    Despite the high prevalence of HIV in adults (11 %) in Malawi, testing among surgical patients is not routine. We examined the feasibility of universal opt-out HIV testing and counseling (HTC) on the surgical wards of Kamuzu Central Hospital in Lilongwe, Malawi, and sought to further delineate the role of HIV in surgical presentation and outcome
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